If 30 articles costrs 300,then the cost of 1 article is ​

Can someone me with my math problem pls my teacher is on my back about this

Which set of side lengths form a right side? a) 3ft,6ft,5ft b)50 in,48in,14in c)53m,48m,24m d)8cm,17cm,14cm

For the following equations, find the ratio of a to b. be sure to show all of your work. a. 3a = 6b b. 15a = 5b